When lawyer Frank Daly was 25, he was told that if he ever wanted to be a judge in Delaware County, he had better register Republican.

Indeed, 33 years later, all 22 judges on the county Court of Common Pleas are Republicans, and a Democrat has never won election, both parties agree.

Each GOP judge has followed a predictable path to the bench by serving as a local solicitor, winning local elected office, or serving in appointed government jobs. Only one sitting judge has won election to the bench without the official party endorsement - and she was previously the GOP county sheriff.

But this year, the Republican Party's traditional advantage in voter registration has dropped to its lowest point in decades, giving Democrats a shot. The judicial primary election is tomorrow; the winners will be on the November ballot.

Daly, who served for 10 years as mayor of Media and who is now running for judge, says the coveted Republican endorsements for the court are determined privately by top GOP party leaders.

"The judges are chosen by Charlie Sexton and John McNichol. It is that simple," Daly said, referring to the powerful longtime Republican Party leaders.

Sexton, for years the Springfield GOP leader, has retired. McNichol is his counterpart in Upper Darby.

"Charlie didn't have anything to do with it" this year, McNichol said. "He wasn't a player."

McNichol said judicial nominees are chosen by a convention of GOP committee chairmen from each community. Judges come up through the party ranks because that is the best way for candidates to become known to leaders and voters, he said.

Delaware County Republican Party Chairman Tom Judge Sr. said judicial candidates are not hand-picked by a few leaders.

"Everyone has the opportunity to run," Judge said. "We pick good candidates with good qualifications, and get [voters] out on Election Day."

Delaware County's one-party dominance of the bench is not dissimilar from the situations in Bucks, Chester and Montgomery Counties, where judges are also virtually all Republican, or in Philadelphia, where the Democrats have a lock.

Lynn A. Marks, executive director of Pennsylvanians for Modern Courts, said she did not believe single-party affiliation on the bench was in itself a problem. "More important than the party is that you have people with various legal backgrounds," Marks said.

Her organization wants appointed, rather than elected, judges in county and state courts.

Last month, Judge Kenneth A. Clouse of Haverford was sent a private reprimand by the state Judicial Conduct Board after complaints of his involvement in Haverford Township politics. Before joining the bench, Clouse was a township commissioner.

McNichol called the Clouse case an isolated incident.

Delaware County's all-GOP bench stands in contrast to the county's changing political makeup.

In 1970, Republicans constituted 78 percent of the county's registered voters. This year, they compose 54 percent.

In tomorrow's primary, five registered Republicans and two Democrats will seek two open spots on each party's ballot. Three of the Republicans are not endorsed by the party and will have to defy conventional wisdom to win a spot on the November ballot.

The officially endorsed GOP candidates are Magisterial District Judge Greg Mallon from Secane and County Council member Mary Alice Brennan from Drexel Hill.

Whether judges are chosen by merit selection or popular vote, there is no perfect system, Mallon said.

"If you want to put me down between the two, I'd go for the popular election because at least the people have the vote," he said.

Running without party endorsements are Magisterial District Judge Richard Cappelli from Concord Township; former State Rep. Tom Gannon from Ridley Township; and C. Scott Shields, mayor of the Borough of Rutledge.

Daly, now Media Borough Council president, and Michael T. Farrell, a lawyer from from Springfield, are running as the endorsed Democrats.

Gov. Rendell recently nominated Daly to fill the seat of retiring Judge Harry J. Bradley until Dec. 31. Daly still awaits legislative confirmation.

When Democrats have been appointed to fill unexpired judicial terms - typically as the result of a deal between a Democratic governor and Republican legislators - they have failed to win judicial retention elections.

GOP strength has been based on its once-overwhelming registration advantage, its well-organized get-out-the-vote organization, and, in some quarters, an oft-expressed dislike of Democratic Philadelphia.

Turnout is also typically low in judicial election years, giving the GOP organization an advantage.

"They are smart and know how to run an organization, and have done it for 100 years," said Farrell, a Democrat.

Delaware County has voted Democratic in recent presidential and gubernatorial races, but the party has largely been unable to win major local elections until last fall, when U.S. Rep. Joe Sestak and State Rep. Bryan Lentz captured seats held by longtime Republicans.

"I think there is going to be a lot more competition for court seats in the future," Democratic Party leader Cliff Wilson said.

Contact staff writer Mari A. Schaefer at 610-892-9149 or mschaefer@phillynews.com.